Paint remover composition and method of making

ABSTRACT

A composition for paint removal and methods of making and of using the composition are provided. The composition comprises tetrahydrofuran (THF), an amine with a molar volume of &lt;100 cm 3 /mol, and a solvent.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application which claims priority from U.S. patent application Ser. No. 16/011,164, filed Jun. 18, 2018, which claims priority from U.S. provisional patent application No. 62/522,417, filed on Jun. 20, 2017, in the United States Patent and Trademark Office. The disclosures of which are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention generally relates to paint removers.

BACKGROUND OF THE INVENTION

Most consumers use paint removers, also commonly referred to as paint strippers, for refinishing antique furniture, or woodworking's (doors, frames, moldings, etc.) in older houses. Many of these items have been painted, and repainted many times over the years. This results in items having multiple layers of paint containing different chemistry types and a different degree of difficulty from being removed. Paint removers are also used in the auto body repair industry to help with vehicle restoration.

Currently methylene chloride and N-Methylpyrrolidone (NMP) are used in the majority of paint removers in the United States. Methylene chloride has been the preferred solvent for use in paint removers for seventy years. Before methylene chloride was introduced, most paint removers consisted of volatile flammable solvents. Paint removers formulated with volatile solvents are extremely flammable and the flammability of these paint removers resulted in fires causing injury and deaths. These paint removers were rapidly replaced with the methylene chloride paint removers because methylene chloride paint removers can be formulated to be non-flammable and are effective in removing multiple layers of paint. The physical characteristics give the methylene chloride molecule the ability to quickly penetrate multiple layers and to soften or dissolve chemically resistant coatings. Methylene chloride does not deplete the ozone layer and is considered to make negligible contributions to smog formation, the green-house effect and acid rain. Like other organic solvents, methylene chloride can be harmful to human health if used improperly.

However, regulations are changing to remove methylene chloride and NMP from the environment. For example, the US Environmental Protection Agency (EPA) is considering a range of possible voluntary and regulatory actions to address risks from the use of methylene chloride-containing paint and coating removal products.

According to the EPA, NMP is both produced and imported into the United States, with use estimated at over 184 million pounds per year. EPA estimates that approximately 9 percent of total NMP usage is for paint and coating removal products.

On Jan. 12, 2017, EPA issued a proposed rule under section 6 of the Toxic Substances Control Act with two proposed approaches for regulating NMP. According to the EPA, one approach is to prohibit the manufacture (including import), processing, and distribution in commerce of NMP for consumer and commercial paint and coating removal; to prohibit commercial use of NMP; and to require manufacturers, processors, and distributors, except for retailers, of NMP to provide downstream notification of these prohibitions throughout the supply chain; and to require limited recordkeeping. According to the EPA, the second approach is a combination of requirements to address unreasonable risks to workers and consumers including to limit the amount of NMP in paint removal products to no more than 35 percent by weight; require formulators to evaluate and identify specialized gloves that protect against skin absorption; require occupational users to have worker protection programs to require that workers wear personal protective equipment to prevent skin and inhalation exposures, require hazard communication for commercial users; and require warning labels for consumers with detailed information on proper ways to reduce exposure.

Thus, there is a need for an alternative paint remover that is effective.

SUMMARY OF THE INVENTION

The present invention generally relates to a paint remover composition and method of making.

In an embodiment of the invention, a paint remover composition comprising tetrahydrofuran (THF) is provided.

In an embodiment of the invention, a paint remover composition comprising a combination of THF and a solvent is provided.

In an embodiment of the invention, the composition comprises: tetrahydrofuran (THF), an amine with a molar volume of <100 cm³/mol, and a solvent.

In an embodiment of the invention, the solvent is selected from the group consisting of aromatic, aliphatic, cycloaliphatic, alcohol, glycol ether-benzene, xylene, toluene, dimethyl benzene, ethylbenzene, aliphatic hydrocarbon with 5 carbon or more, cycloaliphatic hydrocarbon with 5 carbon or more, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, amyl alcohol, ethyleneglycol monomethylether, ethyleneglycol monoethylether, ethyleneglycol monopropylether, ethyleneglycol monobutyl ether, ethyleneglycol monohexylether, phenoxyethanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutylether, propyleneglycol phenyl ether, diethyleneglycol monomethylether, diethyleneglycol monoethylether, diethyleneglycol monopropylether, diethyleneglycol monobutylether, diethyleneglycol monohexylether, diethyleneglycol phenylether, dipropyleneglycol monomethyl ether, dipropyleneglycol monoethyl ether, dipropyleneglycol monopropyl ether, dipropyleneglycol monobutyl ether, dipropyleneglycol phenyl ether, dipropyleneglycol dimethylether, tripropyleneglycol monomethyl ether, tripropyleneglycol monobutylether, ethylene glycol, propylene glycol, glycerol, propanediol, butanediol, 2-methylpropanediol, and a combination thereof.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the embodiments of the present invention is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. The present invention has broad potential application and utility. The following description is provided herein solely by way of example for purposes of providing an enabling disclosure of the invention, but does not limit the scope or substance of the invention.

In an embodiment of the invention, a paint remover composition comprising tetrahydrofuran (THF) is provided. Preferably, THF and at least one other solvent are used in combination.

In an embodiment of the invention, THF and acetone are used in combination in the composition for paint removal. It has surprisingly been found that there is an unexpected synergy between THF and acetone in removing dried paint from a painted surface.

In an embodiment of the invention, THF and acetone are preferably used in combination in a range of 4 weight % to 90 weight % THF and 4 weight % to 90 weight % acetone. THF and acetone can be used in a combination in a range of 4 weight % to 75 weight % of THF and 4 weight % to 75 weight % of acetone. THF and acetone can be used in a combination in a range of 4 weight % to 50 weight % of THF and 4 weight % to 50 weight % of acetone.

Other components may be present in the formulation for paint removal. Non-limiting examples of other such components include, but are not limited to, dye, paraffin wax, antioxidant, surfactant, thickener, fumed silica, corrosion inhibitor, ammonia, peroxide inhibitor (including but not limited to butylated hydroxytoluene), or a combination thereof.

Amine containing corrosion inhibitors include, but are not limited to, primary, secondary, tertiary or quaternary amines, aliphatic, cycloaliphatic or aromatic amines, polyamines, amine salts, such as amine-mineral acid salts, amine-nitrites, amine-carboxylates, amine-phosphates, amine-borates, alkanolamines or alkanolamine-borate complexes, amine-metal complexes, amine containing heterocycles, azoles, and mixtures thereof.

Other components, alone or in combination, may be added in a range of 0 weight % to 25 weight %, more preferably 0.01 weight % to 12.5 weight %.

In an embodiment of the invention, THF and dimethyl sulfoxide (DMSO) are used in combination in the composition for paint removal. It has surprisingly been found that there is an unexpected synergy between THF and DMSO solvents in removing dried paint from a painted surface. THF and DMSO may be used along with acetone. The paint remover composition of the present invention is suitable for chemically stripping paint of various kinds on various surfaces.

In an embodiment of the invention, THF and DMSO are preferably used in combination in a range of 4 weight % to 90 weight % THF and 4 weight % to 90 weight % DMSO. THF and DMSO can be used in combination in a range of 20 weight % to 75 weight % of THF and 20 weight % to 75 weight % of DMSO. THF and DMSO can be used in combination in a range of 4 weight % to 45 weight % of THF and 4 weight % to 45 weight % of DMSO. The weight percentages are based on the total weight percentage of the composition.

In an embodiment of the invention, a composition for paint removal is provided. The paint remover composition generally comprises: 4 weight % to 45 weight % DMSO, 4 weight % to 45 weight % THF or other solvent, 0.5 weight % to 2 weight % cellulose ether thickener, 40 weight % to 60 weight % acetone, 0.2 weight % to 1.0 weight % paraffin, 0 weight % to 2 weight % nonionic surfactant, and 0 weight % to 5 weight % of a primary, secondary or tertiary amine, wherein the weight percentages are based on the weight of the total composition.

A solvent is a single solvent or a combination of solvents. In an embodiment of the invention, the solvent is selected from the group consisting of aromatic, aliphatic, cycloaliphatic, alcohol, glycol ether-benzene, xylene, toluene, dimethyl benzene, ethylbenzene, aliphatic hydrocarbon with 5 carbon or more, cycloaliphatic hydrocarbon with 5 carbon or more, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, amyl alcohol, ethyleneglycol monomethylether, ethyleneglycol monoethylether, ethyleneglycol monopropylether, ethyleneglycol monobutyl ether, ethyleneglycol monohexylether, phenoxyethanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutylether, propyleneglycol phenyl ether, diethyleneglycol monomethylether, diethyleneglycol monoethylether, diethyleneglycol monopropylether, diethyleneglycol monobutylether, diethyleneglycol monohexylether, diethyleneglycol phenylether, dipropyleneglycol monomethyl ether, dipropyleneglycol monoethyl ether, dipropyleneglycol monopropyl ether, dipropyleneglycol monobutyl ether, dipropyleneglycol phenyl ether, dipropyleneglycol dimethylether, tripropyleneglycol monomethyl ether, tripropyleneglycol monobutylether, ethylene glycol, propylene glycol, glycerol, propanediol, butanediol, 2-methylpropanediol, and a combination thereof.

In an embodiment, the solvent is selected from the group consisting of THF, toluene, DMSO, dioxalane, 1,2 trans dichloroethylene, and a combination thereof. The solvent may be a combination of THF and DMSO. THF and DMSO in combination have found to have a synergistic effect in a paint remover.

Other solvent combinations demonstrating a synergistic effect in a paint remover include, but are not limited to, THF and DMSO; toluene and DMSO; Dioxalane and DMSO; 1,2 trans dichloroethylene and DMSO; and a combination thereof.

In an embodiment of the present invention, the composition comprises tetrahydrofuran (THF), an amine with a molar volume of <100 cm³/mol, and a solvent.

The tetrahydrofuran (THF) may be present in an amount of 50 weight % to 90 weight %, wherein the weight percentages are based on the weight of the composition. The amine may be present in an amount of 1 weight % to 10 weight %, wherein the weight percentages are based on the weight of the composition. The solvent may comprise a hydrocarbon. The solvent may be an alcohol or a glycol ether.

The composition may comprise water. The water may be present in an amount up to 20 weight %, wherein the weight percentages are based on the weight of the composition.

The molar volume of the amine may be <100 cm³/mol. The molar volume of the amine may be <30 cm³/mol. The amine is selected from the group consisting of ammonia, hydroxylamine, dimethylamine, ethanolamine, pyrrolidine, and a combination thereof.

The composition may comprise a solvent evaporation retarder such as a paraffin wax. The composition may comprise a cellulosic thickener. Non-limiting examples of cellulosic thickeners are hydroxypropyl methyl cellulose, hydroxypropyl cellulose, and a combination thereof. The composition may comprise an amine containing corrosion inhibitor.

EXAMPLES Example 1

Paint stripping tests were conducted in accordance with the present invention. The paint stripping test used a proposed formula in accordance with the present invention in which a solvent was varied in the tests. Stripping ability was measured after 15 and 30 minutes by scraping layers of paint off a board using a plastic scraper. Scraping was made at a low angle from the board without using pressure that would dig into the paint. The purpose was to see how much paint would remove with ease in the test in order to more accurately evaluate the effect of the chemical solvent on the paint without agitation (other than to remove the loosened and softened paint layers and not layers beneath that have not reacted to the stripper in the time period allowed).

The paint panel was prepared as follows using Rust Oleum's Oil based paints:

First layer=Blue

Second layer=White

Third layer=Green

Fourth layer=Yellow

Fifth layer=Red

The fifth layer was the top layer, and there were five layers in total. Each layer set for one 24 hour period before the next layer. Each coat of paint was rolled on in a usual manner using a standard 6″ long paint roller with a ¼″ nap. After the last application of paint, the boards were placed at 50 C for 30 days in order to cure further.

The stripper formulation tested is set forth in Table 1:

TABLE 1  10.0 weight % toluene  0.8 weight % paraffin wax (127° F. melting point)  1.25 weight % cellulose ether thickener (Tylose PS0810001)  29.5 weight % solvent (varied for testing purposes) 46.95 weight % acetone  10.0 weight % methanol  0.5 weight % nonionic surfactant (Tomadol 900)  1.0 weight % Aqua Ammonia (26 Deg. Baume) Note that weight percentages are based on the total weight of the formulation.

The solvents tested were:

(1) Dimethyl sulfoxide (DMSO), (2) toluene, (3) 1, 2 trans dichloroethylene, (4) Dioxalane, and (5) Tetrahydrofuran (THF).

The order of performance, greater to lower, of these 5 solvents were as follows with THF being the greater and 1, 2 transdichloroethylene being the lower:

-   -   THF     -   Toluene     -   Dioxalane     -   DMSO     -   1, 2 transdichloroethylene

Blends of the experimental solvents were also tested.

The base blend for these experiments was:

TABLE 2 24.75 weight % DMSO 24.75 weight % solvent (varied for testing purposes)  1.25 weight % cellulose ether thickener (Tylose) 46.95 weight % acetone  0.8 weight % paraffin  0.5 weight % nonionic surfactant (Tomadol 900)  1.0 weight % aqua ammonia

Note that weight percentages are based on the total weight of the formulation

The stripping test results were visually inspected after setting 15 and 30 minutes.

All of the blends tested demonstrated synergy; however, the THF/DMSO combination was the best performing synergistic blend. The order of performance found, from greater to lesser, was with THF/DMSO blend being greater and 1,2 trans dichloroethylene/DMSO blend being lesser:

-   -   THF/DMSO     -   Toluene/DMSO     -   Dioxalane/DMSO     -   1,2 trans dichloroethylene/DMSO

THF and DMSO were tested in various ratios of THF/DMSO: 50/50, 100/0, 0/100, 75/25, 25/75, 90/10, 10/90, 82.5/17.5, and 17.5/82.5.

Example 2

Paint stripper formulations were tested in accordance with the present invention and are set forth in Table 3. The formulations were in a form of a liquid or an aerosol.

TABLE 3 Components Weight Percentage (%) THF 49.5 Dye 0.002 Paraffin Wax (refined) 0.25 BHT 0.025 Acetone 40 to 45 Surfactant 1 Fumed Silica 0 to 5 Thickener  0.1 to 1.25 Diglycolamine 0.5 Aqua Ammonia 5

Example 3

TABLE 4 Molar Volume of Primary Solvents Density Molar Vol. Ingredient (wt. %) Mw (g/mol) (g/cm³) (cm³/mol) Tetrahydrofuran 72.1 0.888 81.23

TABLE 5 Miscibility Test of Primary Solvent with Aqua Ammonia (15 g total) Primary Solvent Cosolvent Solvent NH₄OH* Appearance   85% Tetrahydrofuran — 15% Phase separation 78.5% Tetrahydrofuran 6.5% Methanol 15% Miscible - clear 78.5% Tetrahydrofuran 6.5% DMSO 15% Phase separation   72% Tetrahydrofuran  13% DMSO 15% Phase separation *30% NH₄OH in water

TABLE 6 Evaluation of Primary Solvents in Paint Remover* Ex. 1 Ingredient (wt. %) Tetrahydrofuran 71.5 Xylene 5 Tylose PSO810001 1.5 Paraffin wax 0.5 Methanol 6.5 30% Ammonia in H₂O 15

TABLE 7 Stripping Performance of Primary Solvents in Paint Remover Time to strip 2014 Chevy Cruise hood Paint Layers Example Primary Solvent (min) Removed Ex. 1 Tetrahydrofuran 98 All

TABLE 8 Evaluation of Amines in Paint Remover Ingredient (wt. %) Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Tetrahydrofuran 93.75 67.5 81.75 72.5 87.75 87.75 87.75 Calumet LVP 100  5  5  5  5  5  5  5 Tylose PSO810001  0.75  0.75  0.75  0.75  0.75  0.75  0.75 Paraffin wax  0.5  0.5  0.5  0.5  0.5  0.5  0.5 Methanol  6.25  6.25 30% Ammonia 20 in H₂O 50% Hydroxylamine 12 in H₂O 40% Dimethylamine 15 in H₂O Pyrrolidine  6 Ethanolamine  6 Dimethylethanolamine  6

TABLE 9 Stripping Performance of Amines in Paint Remover vs. Molar Volume Time to Strip Molar 2004 Vol. Impala Paint Mw Density (cm³/ trunk Layers Example Amine (g/mol) (g/cm³) mol) (min) Removed Ex. 2 None 44 Clearcoat Ex. 3 Ammonia 17.03 0.73 23.3 10 All Ex. 4 Hydroxylamine 33.03 1.21 27.3 11 All Ex. 5 Dimethylamine 45.08 0.67 67.3 15 All Ex. 7 Ethanolamine 61.08 1.01 60.5 21 Clearcoat Basecoat Some primer Ex. 6 Pyrrolidine 71.12 0.87 89 22 Clearcoat Basecoat Some primer Ex. 8 Dimethylethan- 89.14 0.89 100.2 32 Clearcoat olamine

TABLE 10 Evaluation of Increased Amine Level in Paint Remover Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ingredient (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) Tetrahydrofuran 93.75 77.5 67.5 57.5 81.75 Calumet LVP 100 5 5 5 5 5 Tylose PSO810001 0.75 0.75 0.75 0.75 0.75 Paraffin wax 0.5 0.5 0.5 0.5 0.5 Methanol 6.25 6.25 6.25 30% Ammonia in 10 20 30 H₂O 50% Hydroxylamine 12 in H₂O

TABLE 11 Stripping Performance of Formulas with Increased Amine Level Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Time to strip >180 140 150 >180 >180 2014 Cruise hood (min) Paint Layers Clearcoat Clearcoat All All Clearcoat stripped Basecoat Basecoat Basecoat some primer some primer Time to strip >180 32 30 40 45 2013 Impala trunk Paint Layers Clearcoat All All All All stripped

TABLE 12 Evaluation of Increased Cosolvent Solvent Level in Paint Remover Ex. 14 Ex. 15 Ex. 16 Ingredient (wt. %) (wt. %) (wt. %) Tetrahydrofuran 74 64 54 Calumet LVP 100 5 5 5 Tylose PSO810001 0.75 0.75 0.75 Paraffin wax 0.5 0.5 0.5 Methanol 4.75 14.75 24.75 30% Ammonia in 15 15 15 H₂O

TABLE 13 Stripping Performance of Formulas with Increased Cosolvent Solvent Level Ex. 14 Ex. 15 Ex. 16 Time to strip 145 210 >360 2014 Cruise hood (min) Paint Layers All All Clearcoat stripped Basecoat Some primer

It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements. 

What is claimed is:
 1. A composition comprising: tetrahydrofuran (THF) in an amount of 50% by wt. to 90% by wt. based on the total weight of the composition, an amine with a molar volume of <100 cm³/mol, a solvent that renders the composition miscible, the solvent is an alcohol, a glycol ether, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, amyl alcohol, ethyleneglycol monomethylether, ethyleneglycol monoethylether, ethyleneglycol monopropylether, ethyleneglycol monobutyl ether, ethyleneglycol monohexylether, phenoxyethanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutylether, propyleneglycol phenyl ether, diethyleneglycol monomethylether, diethyleneglycol monoethylether, diethyleneglycol monopropylether, diethyleneglycol monobutylether, diethyleneglycol monohexylether, diethyleneglycol phenylether, dipropyleneglycol monomethyl ether, dipropyleneglycol monoethyl ether, dipropyleneglycol monopropyl ether, dipropyleneglycol monobutyl ether, dipropyleneglycol phenyl ether, dipropyleneglycol dimethylether, tripropyleneglycol monomethyl ether, tripropyleneglycol monobutylether, ethylene glycol, propylene glycol, glycerol, propanediol, butanediol, 2-methylpropanediol, or a combination thereof and water in an amount up to 20% by wt., based on the total weight of the composition, wherein the composition is miscible and is a paint remover.
 2. The composition according to claim 1, wherein the amine is present in an amount of 1 weight % to 10 weight %, wherein the weight percentages are based on the weight of the composition.
 3. The composition according to claim 1, wherein the amine is selected from the group consisting of ammonia, hydroxylamine, dimethylamine, ethanolamine, pyrrolidine, and a combination thereof.
 4. The composition according to claim 1, wherein the molar volume of the amine is <30 cm³/mol.
 5. The composition according to claim 1, wherein the amine is selected from the group consisting of ammonia, hydroxylamine, and a combination thereof.
 6. The composition according to claim 1, further comprising a solvent evaporation retarder.
 7. The composition according to claim 1, wherein the solvent evaporation retarder is a paraffin wax.
 8. The composition according to claim 1, further comprising a cellulosic thickener.
 9. The composition according to claim 1, wherein the cellulosic thickener is selected from the group consisting of hydroxypropyl methyl cellulose, hydroxypropyl cellulose, and a combination thereof.
 10. The composition according to claim 1, further comprising an amine containing corrosion inhibitor.
 11. The composition according to claim 1, wherein the composition excludes a surfactant.
 12. The composition according to claim 1, wherein water is present in an amount up to 14% by weight based on the total weight of the composition.
 13. The composition according to claim 1, wherein water is present in an amount up to 10.5% by weight based on the total weight of the composition.
 14. The composition according to claim 1, wherein water is present in an amount up to 7% by weight based on the total weight of the composition.
 15. The composition according to claim 5, wherein water is present in an amount up to 14% by weight based on the total weight of the composition.
 16. The composition according to claim 5, wherein water is present in an amount up to 10.5% by weight based on the total weight of the composition.
 17. The composition according to claim 5, wherein water is present in an amount up to 7% by weight based on the total weight of the composition. 